1. Field of the Invention
The present invention relates to a vehicular lamp and more particularly to a vehicular lamp that employs a light emitting device such as a light emitting diode (called an “LED”) as a light source thereof.
2. Prior Art
A vehicular lamp that includes an LED which is the light source and a reflector which reflects light from the LED is disclosed in Japanese Patent Application Laid-Open (Kokai) No. 11-306810.
This lamp is constructed such that, as shown in FIG. 5, within the lamp chamber defined by a lamp body 1 and a front lens 2, a plurality of LEDs 4a are provided to face forward (right side in FIG. 5), and a single LED 4b is provided below a reflector 3 to face upward (top side in FIG. 5). Thus, the lamp of this prior art includes a direct light emitting type lamp structure A, which distributes light emitted from the LEDs 4a mainly directly in the forward direction, and a reflection type lamp structure B, which reflects light emitted from the LED 4b and distributes it in the forward direction by the reflector 3.
However, in the direct light emitting type lamp structure A, so as to emit light emitted from the LEDs 4a that have a high directivity in a large area of the front lens 2, a large number of LEDs are correspondingly required. This causes a problem of high cost.
In the reflection type lamp structure B, the LED 4b is disposed at a position diagonally in front of and below the reflector 3; and thus there is a problem that the lamp structure is complicated.
With the above prior art lamp in mind, the inventors of the present application conceived a structure in which “a mushroom-shaped light guide in which an umbrella portion is formed at its front end is used for internal reflection of light which is emitted from an LED and is incident from the rear end portion of the bar-shaped base portion in the light guide such that the light becomes parallel light fluxes by an internal reflection surface formed in the umbrella portion at the front end, thus emitting the light toward a reflector.” The inventors made a prototyped of such a light guide, and it was confirmed that such light guide solves the problems of the prior art lamp structure; and the present invention was made.